even china, north korea's long-time ally, has expressed firm opposition to the nuclear tests. we'll have more on this breaking story later on on "gma." >>> we turn to a change of the top of the catholic church. pope benedict made the bombshell announcement he is stepping down. >> at age 85, the pope says he cannot keep up with the job. nick schifrin joins us from rome with more. good morning, nick. >> reporter: good morning, rob. good morning, diana. pope benedict is a shy leader. but he's unpredictable, unprecedented. and it might just guarantee his legacy. at 85, he is silver-haired and cerebral and says he simply can't keep up. pope benedict xvi tells his cardinals in latin, quote, i had to recognize my incapacity to adequately fulfill the ministry entrusted to me. in the last year, benedict grew increasingly frail. >> he certainly slowed down a bit. you could tell he had trouble negotiating steps. he started using the cane several months ago. >> reporter: but the german pope never slowed down, putting the church on an orthodox path. he opposed homosexuality and female prie